Crystal Developments for the Homogeneous Hadron Calorimeter Detector Concept

Transcription

1 Crystal Developments for the Homogeneous Hadron Calorimeter Detector Concept Ren-yuan Zhu California Institute of Technology March 21, Linear Colliders Workshop of the Americas, Eugene

2 Homogeneous Hadron Calorimeter A Fermilab team (A. Para et al.) proposed a total absorption homogeneous HCAL detector concept to achieve good jet mass resolution by measuring both Cherenkov and Scintillation light. It also eliminates the dead materials between classical ECAL and HCAL. This longitudinal segmented crystal HCAL is possible because of the latest development in large area compact readout devices. Requirements for the materials to be used for HHCAL: Short nuclear interaction length: ~ 20 cm. Good UV transmittance: UV cut-off < 350 nm. Some scintillation light, not necessary bright and fast. Cost-effective material: < $2/cc for 100 m 3! Radiation hardness is not crucial at the ILC/CLIC. A series of workshops on material development for HHCAL: 1 st 2/19/2008 at SIC, Shanghai, 2 nd 5/9/2010 at IHEP, Beijing, 3 rd 10/30/2010 at Knoxville, will go with SCINT, CALOR & IEEE NSS. 2

3 The HHCAL Detector Concept See A. Para, H. Wenzel, Callor2010: GEANT simulations show a jet energy resolution of better than 20%/ E after corrections. R.-Y. Zhu, ILCWS-08, Chicago: a HHCAL cell with pointing geometry 3

4 Industrial Halide Growth: Kharkov A. Gektin: Talk at the 2 nd Workshop for HHCAL 4

5 Industrial Oxide Growth: SICCAS Guohao Ren: Talk at the 2 nd Workshop for HHCAL 5

6 Cost for Crystal Growth A. Gektin: for mass produced Si crystals raw materials share 70% of the cost Crystal cost structure (Si) 68% - raw material 10% - crucible 8% - system cost 4% - labor cost 4% - power 6% - other Single Crystal Si Ingot 6

7 Candidate Crystals for HHCAL Parameters Bi 4 Ge 3 O 12 (BGO) PbWO 4 (PWO) PbF 2 PbClF Bi 4 Si 3 O 12 (BSO) ρ (g/cm 3 ) ? λ I (cm) λ max τ decay (ns) /10? λ max (nm) /420? Cut-off λ (nm) Light Output (%) /0.37? Melting point ( C) Raw Material Cost (%)

8 Crystal for Homogeneous HCAL Crystals of high density, good UV transmittance and some scintillation light, not necessary bright and fast, are required. The volume needed is 70 to 100 m 3 : cost-effective material. Following 2/19/08 workshop at SICCAS, 5 x 5 x 5 cm samples evaluated. 8

9 Cherenkov Needs UV Transparency Cherenkov figure of merit Using UG11 optical filter Cherenkov light can be effectively selected with negligible contamination from scintillation 9

10 Scintillation Selected with Filters UG11/GG400 optical filter effectively selects Cherenkov/scintillation light 10

11 No Discrimination in Front Edge Consistent timing and rise time for all Cherenkov and scintillation light pulses observed. S S S C C C 11

12 Ratio of Cherenkov/Scintillation 1.6% for BGO and 22% for PWO with UG11/GG400 filter and R2059 PMT, which is configuration dependent. BGO 12

13 PbF 2 Crystal Samples A total of 116 samples with various rare earth doping were grown by vertical Bridgman method at SIC and Scintibow. SIC samples: grown in platinum crucible, 1.5 X 0 (14 mm) cube. Scintibow samples: grown in graphite crucible, Φ 22 x 15 mm. Photo: SIC sample/scintibow sample. 13

14 Scintillation was Observed in PbF 2 :Gd Scintillation of PbF 2 (Gd) PbF 2 (Gd) Response to MIP of 1 GeV/c Fast Scintillation of 6.5 p.e./mev with decay time of less than 10 ns C. Woody et al., IEEE Trans. Nucl. Sci. 43 (1996)

15 Luminescence Observed in PbF 2 Consistent Photo- and X-luminescence observed in doped PbF 2 samples grown by Prof. Dingzhong Shen of SIC/Scintibow. 15

16 Rare Earth Doped PbF 2 Multi-ms decay time observed, indicating f-f transitions of these rare earth elements which is too slow to be useful. 16

17 Anode Current Anode current measured for doped PbF2 samples is at the same level as undoped crystals, indicating weak light. 17

18 137 Cs Pulse Height Spectra So far, no detectable scintillation was found R.H. Mao et al., IEEE TNS Vol 57 No 6 (2010)

19 PbClF Crystals Guohao Ren of SIC: Talk at the 2 nd Workshop for HHCAL D= 7.11g/cm 3 Melting point =608 C Space group=p/4nmm a=4.10å;c= 7.22Å Crystal structure of PbClF PbClF Crystal samples grown at SICCAS 19

20 PbFCl Samples PbFCl-1 PbFCl-2 PbFCl-3 PbFCl-4 PbFCl-5 ID PbFCl-1 PbFCl-2 PbFCl-3 PbFCl-4 PbFCl-5 Doping -- Na 0.5at% Dimension (mm) 10x10x2 10x10x2 30x10x5 20x10x3 ~10x10x9 ID PWO PbFCl-1 PbFCl-2 PbFCl-3 PbFCl-4 PbFCl-5 X-luminescence 420 nm L.O. (% PWO) L.O. (% BGO)

21 X-Luminescence & Transmittance Consistent X-luminescence peaked at 420 nm observed in all PbFCl samples. Transmittance cut-off at 300 nm. 21

22 137 Cs Spectrum & Decay Kinetics Weak scintillation light with decay time of 24 ns observed in all PbFCl samples. Preliminary 22

23 BSO Crystals Hu Yuan of SIC: Talk at the 2 nd Workshop for HHCAL Nov. 2008: Φ2.5 x 12 cm Feb Φ2 x 17 cm May 2009 Oct. 2009: 2 x 18 cm Φ5.5 x 12 cm 23

24 BSO Samples BSO-1 BSO-2 BSO-3 BSO-4 BSO-5 BSO has two phases 24

25 Excitation, Emission & Transmittance Improvement of UV absorption observed. The cut-off of transmission spectra moved toward 300 nm. Absorption visible between 350 and 600 nm. 25

26 137 Cs Spectrum & Decay Kinetics Light output is about 15% of BGO, should be improved to 20% after the visible absorption removed. Decay time constant is ~100 ns. 26

27 Summary The HHCAL is an interesting detector concept providing a unprecedented combination of e/ɣ and jet mass resolutions. The crucial issue is to develop high quality materials of low cost: < $2/cc. Among all crystals, PbF 2, PbClF and BSO seem the best candidates to meet the cost goal. While consistent photo and x- luminescence was found in Er, Eu, Gd, Ho, Pr, Sm and Tb doped PbF 2 samples, their decay time is at ms scale as expected from the f-f transition of the rare earth elements. The scope of this R&D is now expanded to a broad range other of materials, including scintillating glasses and ceramics etc. See presentations at the 2 nd and 3 rd HHCAL Workshops. 27

28 2 nd Workshop for the HHCAL May 9, 2010, Beijing: 1) HHCAL and General Requirement: Gene Fisk, FNAL: Fermilab's History in the Development of Crystals, Glasses and Si Detector Readout for Calorimetry Adam Para, FNAL: Scintillating Materials for Homogeneous Hadron Calorimetry Steve Derenzo, LBL: Search for Scintillating Glasses and Crystals for Hadron Calorimetry Paul Lecoq, CERN: A CERN Contribution to the Dual Readout Calorimeter Concept 2) Materials for HHCAL (I) : Alex Gektin, SCI: Crystal Development for HHCAL: Physics and Technological Limits Liyuan Zhang, Caltech: Search for Scintillation in Doped Lead Fluoride for the HHCAL Detector Concept Guohao Ren, SIC: Development of Halide Scintillation Crystals for the HHCAL Detector Concept Hui Yuan, SIC: BSO Crystals Development with the Modified Multi-crucible Bridgman Method for the HHCAL Detector Concept 3) Materials for the HHCAL (II) followed by discussions Mingrong Zhang, BGRI: R&D on Scintillation Crystals and Special Glasses at BGRI Tiachi Zhao, U Washington/IHEP and Ningbo University: Study of Dense Scintillating Glass Samples Jing Tai Zhao, SIC: Status of Scintillating Ceramics and Glasses at SIC and Their Potential Applications for the HHCAL Detector Concept Richard, Wigmans, Texas Tech University: Some thoughts about homogeneous dual-readout calorimeters 28

29 3 rd Workshop for the HHCAL October 31, 2010, Knoxville: 1. A. Para, Prospects for High Resolution Hadron Calorimetry 2. G. Mavromanolakis, Studies on Dual Readout Calorimetry with Meta-Crystals 3. D. Groom, Degradation of resolution in a homogeneous dual readout hadronic calorimeter 4. S. Derenzo, High-Throughput Synthesis and Measurement of Candidate Detector Materials for Homogeneous Hadronic Calorimeters 5. M. Poulain, Fluoride Glasses: State of Art and Prospects 6. I. Dafinei, High Density Fluoride Glasses, Possible Candidates for Homogeneous Hadron Calorimetry 7. P. Hobson, Prospects for Dense Glass Scintillators for Homogeneous Calorimeters 8. G. Dosovitski, Potential of Crystalline, Glass and Ceramic Scintillation Materials for Future Hadron Calorimetry 9. Tianchi Zhao, Study on Dense Scintillating Glasses 10. Jin-tai Zhao, BSO-Based Crystal and Glass Scintillators for Homogeneous Hadronic Calorimeter 11. Guohao Ren, Development of RE-Doped Cubic PbF2 and PbClF Crystals for HHCAL 12, N. Cherepy, Transparent Ceramic Scintillators for Hadron Calorimetry 13. J. Dong, Experimental Study of Large Area GEM 14. H. Frisch, The Development of Large-Area Flat-Panel Photodetectors with Correlated Space and Time Resolution 29